PHANTOMa
From Serial Experiments Lain wiki
An in-game sequence of PHANTOMa, bearing resemblance to 90s-era dungeon crawling computer RPGs such as Might and Magic and Dungeon Master.
A MMORPG popular with children that is actually a front for KIDS, a project to harness the collective psychic potential of children based on the research findings of Professor Hodgeson.
The gameplay mostly involves killing monsters and other players. During Layer 04, a man finds PHANTOMa and a tag game played by kindergartners merging, resulting in him shooting a young girl with an in-game weapon. When Lain Iwakura of the Wired asks Taro what is fun about the game, he responds with "Nobody knows what's fun and why."
In Layer 06, the latent psychic abilities of these children is used to create a giant image of Lain in the sky.